igmp-snooping max-response-time
Function
The igmp-snooping max-response-time command sets the maximum response time for IGMP General Query messages in a VLAN.
The undo igmp-snooping max-response-time command restores the default maximum response time for IGMP General Query messages in a VLAN.
By default, the maximum response time for IGMP General messages in a VLAN is 10 seconds.
Usage Guidelines
Usage Scenario
Setting IGMP snooping parameters helps improve multicast forwarding performance. By setting the maximum response time for IGMP General Query messages, you can:
- Control the deadline for a host to send an IGMP Report message. When hosts are required to respond to IGMP General Query messages quickly, set a short maximum response time. To avoid congestion caused by a large number of IGMP messages sent by hosts, set a long maximum response time.
- Adjust the aging time of member ports. When the wireless access controller receives a Report message, it starts the aging timer for the member port. The aging time is calculated using the following formula: Aging time = General query count x General query interval + Maximum response time for General Query messages. The igmp-snooping max-response-time command sets the maximum response time. The General query count is set by the igmp-snooping robust-count command, and the general query interval is set by the igmp-snooping query-interval command.
The wireless access controller sets the maximum response time field in General Query messages to the value set by the igmp-snooping max-response-time command.
Prerequisites
IGMP snooping has been enabled globally using the igmp-snooping enable (system view) command.
Follow-up Procedure
- Run the igmp-snooping query-interval command to set the interval at which General Query messages are sent.
- Run the igmp-snooping lastmember-queryinterval command to set the interval at which Group-Specific Query messages are sent.
Precautions
The configuration takes effect only after you run the igmp-snooping enable (VLAN view) command to enable IGMP snooping in the VLAN.
The maximum response time for General Query messages must be shorter than the interval at which General Query messages are sent. Otherwise, the wireless access controller may delete multicast memberships that should not be deleted.
